Is the message conveyed in the following yellow traffic sign considered legal?

- The sign is not a traffic sign; hence the message is not legal.
- The message in the traffic sign is limited to an urban road only.
- The yellow sign is an advertisement sign of a party having interest.
- Correct answer: The traffic sign is legal for all matters.
Why this is the answer
The correct answer in the official bank: The traffic sign is legal for all matters.
The yellow sign was placed on the road by the authorized authority, so it is a binding traffic sign like any other. Its yellow colour and free text do not make it an advertisement. Its message, to keep licence plates clear and visible, applies to all drivers on this road and is not limited to urban roads.